This invention relates generally to film, video, and electronic imaging technology and, more particularly, to an apparatus and method for special effects moving image photography.
In photography and image processing every method and piece of equipment has both advantages and limitations when it comes to manipulating the visual qualities of images. Inventors have attempted to overcome limitations on, and add functionality to, certain prior art camera devices by devising systems which produce, and in some cases record, multiple optical images.
One group of such prior art consists of camera devices designed to use black and white film to reproduce color images. In these devices each of the multiple image paths is filtered to transmit a different portion of the color information. An example of such a camera device is shown in U.S. Pat. No. 2,027,369 to Bourges, which discloses multiple motion picture cameras, each fitted with an objective lens, which are mounted together in a unit, and combined with multiple beam splitter mirrors positioned in front of their objective lenses such that the resulting angle of view of the cameras is identical.
The use of beam splitter mirrors in front of multiple objective lenses creates significant optical limitations. A two camera arrangement which uses a single such mirror will limit how wide-angle the objective lenses can be without xe2x80x9cvignettingxe2x80x9d the image. In a system with three or more cameras such as the Bourges device, (and with the resulting need for multiple beam splitter mirrors) the problem would be acute. It is also practically impossible to use zoom lenses in such a system, because of the difficulty of matching their focal lengths.
Camera devices that create multiple optical images of other configurations are also known in the art. One such group of prior art consists of so called xe2x80x9cthree chipxe2x80x9d video cameras, which utilize three electronic image sensors to produce color images. An example of one of these devices is U.S. Pat. No. 4,275,412 to Contant, which discloses a beam splitter prism positioned behind a single, shared objective lens, with the prism used to divide the image produced by the objective lens and direct a copy of that image to each of three electronic imaging sensors. Placing the beam splitter behind the objective overcomes the above-described limitations, and prisms are conventional to be optically superior to mirror or pellicle beam splitters for this purpose. These prior art devices create multiple optical images, but the individual sensors are incapable of producing images that contain complete picture information. A combination of the information from all of the sensors is necessary to reproduce the color of the original scene. The limitation is the same whether the cause is filters inserted in each optical path or the design of the imaging sensors.
This type of video camera is also limited by the fact that it is incapable of making separate recordings of the images produced by the multiple imaging sensors. Information from the three sensors is first combined electronically, and a single recording is made of the combined information. These camera devices are further restricted by the limited functionality of their electronic image combination means. The above limitations prevent such camera devices from realizing potential additional advantages of utilizing multiple, rather than single, image sensors or film strips.
Camera devices that utilize multiple image recording devices in combination with a beam splitter positioned behind an objective lens are also disclosed in the prior art. One example of such a device is a device designed to use black and white film to reproduce color images. This device discloses three film transport mechanisms associated with multiple image paths, each of which is filtered to transmit a different portion of the color information, and all of which are synchronized to make their separate exposures simultaneously. As part of the original xe2x80x9cTechnicolorxe2x80x9d process, the filtered images were developed and combined in a motion picture film laboratory.
The synchronization of the multiple camera mechanisms is maintained to a very high degree of precision because, if they were not, the resulting images would be rendered unusable by color distortions. Precise adherence to the synchronization pattern is insured by fixed mechanical interconnections between the multiple camera mechanisms, and between those mechanisms and the camera""s motor. The fact that it includes no provision for individually adjusting the xe2x80x9cspeedxe2x80x9d (frames per second/f.p.s.), and the synchronization or relative timing of the three camera mechanisms prevents this camera device from realizing potential additional advantages.
Another example disclosed in the prior art is not as limited. This device is specifically designed to produce the effect of an instantaneous change from conventional to slow motion moving images. The effect is completed by editing or xe2x80x9ccuttingxe2x80x9d from an image sequence recorded at one camera speed to an image sequence recorded at a different camera speed. In order to create the required image sequences this device allows two camera mechanisms with a matching point of view to operate at different speeds relative to each other. This device is limited by the fact that there is no incorporated or extent device compatible with this or other camera devices for coordinating or synchronizing in a precise manner the exposure cycles of cameras operating at different speeds and/or when the exposure cycles of those cameras are synchronized and offset relative to each other, and the cameras are operating at low speeds, i.e., below 15 f.p.s.
Certain other limitations on the above described prior art devices result from the fact that their film strips or image sensors are exposed directly to the image formed by an objective lens. In such an arrangement there is only a short distance between the rear of the objective lens and the focal planes of the multiple images. Consequently there is extremely limited space available for a beam splitter prism and the associated film gate structures or image sensor devices. These space restrictions prevent the use of larger camera mechanisms such as existing film or video cameras, and necessitate the use instead of specially constructed and permanently installed camera mechanisms or electronic image detectors.
One solution to these space restrictions calls for the use of optical relays. Optical relays, which extend the distance between the rear of an objective lens and the focal plane of the image sensor or film gate into which the final image is projected, are generally known in the prior art for use with a single camera device. An example of a motion picture camera optical relay is shown in U.S. Pat. No. 5,727,236 to Frazier, which discloses an arrangement of an objective lens, a field lens and a relay lens such that the image originally formed by the objective lens is transmitted by the other lenses to the film of a film camera or the electronic imaging detector of a video camera. The Frazier device and others also allow the focus of the final image to be adjusted by the relay lens instead of the objective lens. However, the prior art has failed to provide a multiple axis optical relay having a plurality of associated camera mechanisms.
The ability of prior art moving image camera devices, including those which produce multiple images, to control the extremely short xe2x80x9cburstsxe2x80x9d of electronic flash lighting is also restricted by limitations in conventional camera shutters. A conventional flash device currently in use in the motion picture industry emits light in bursts that have a duration of {fraction (1/100,000)}th of a second. In contrast, the conventional shutter in a typical professional film camera, limited by its relatively compact size, and operated at normal camera speed (i.e., 24 f.p.s.), can generate a maximum shutter xe2x80x9cspeedxe2x80x9d (minimum exposure time) of only {fraction (1/200)}th of a second. A potential advantage of multiple image camera devices over conventional cameras in regard to manipulating the visual qualities of flash illuminated images is therefore limited by the inability of conventional camera shutters to operate at higher xe2x80x9cspeedsxe2x80x9d.
It is therefore a broad object of this invention to provide an improved multiple moving image sequence recording camera device, which may be used to create a broad variety of image manipulations and visual effects.
A more specific object of the present invention is to provide a camera apparatus capable of creating, and making moving image recordings of multiple, matching, high-quality copies of an image originally produced by an objective lens.
Another object of the present invention is to provide a camera apparatus capable of making separate adjustments to multiple aspects of the photographic characteristics of each of those image copies. In particular, a camera apparatus capable of making separate and wide ranging adjustments to the focus, f-stop, and shutter speed characteristics of multiple images.
A still further object of the invention is to provide a multiple moving image recording device distinguished by its ability to control the temporal characteristics of the exposure cycles of its component camera mechanisms, both individually and in relation to each other, in a manner that is both adjustable and precise. In particular, a device capable of offsetting the timing of the exposure cycles of each component camera relative to the other cameras in increments of a small fraction of a cycle, and maintaining with a high degree of precision the degree to which they are offset. Furthermore, a device capable of maintaining a given synchronization pattern for its component camera devices even if their exposure cycles are offset, and/or running at different speeds, and/or the synchronization pattern itself changes over time, and/or they are operating at lower than normal frame rates.
In the present invention these purposes, as well as others which will be apparent, are achieved generally by providing a sturdy plate for supporting a plurality of camera mechanisms, each camera mechanism provided with an adjustable support device, and connected to a multiple axis optical relay, which may contain additional shutter devices. Each camera mechanism and its associated optical relays, shutters, and lenses can be individually controlled and adjusted to allow an operator a broad range of photographic settings to achieve a smooth, continuous, natural motion moving image recording.
The present invention provides the ability to create and record multiple, matching, high-quality copies of an image originally produced by an objective lens. The camera also has the ability to make separate adjustments to multiple aspects of the photographic characteristics of each of those image copies. In particular, it is possible to adjust the focus and f-stop of each image. Further, the camera has the ability to control the temporal characteristics of the exposure cycles of its component camera mechanisms, both individually and in relation to each other, in a manner that is both adjustable and precise. Unlike the prior art, the present invention is capable of offsetting the timing of the exposure cycle of each component camera relative to the other cameras in increments of a small fraction of a cycle, and maintaining with a high degree of precision the degree to which they are offset. Moreover, the camera can maintain a given synchronization pattern for its component camera mechanisms even if their exposure cycles are offset and/or running at different speeds and/or the synchronization pattern itself changes over time.
The combination of the above described features results in the ability of the present invention to record overlapping segments of time. In turn, that ability makes it possible for the present invention to utilize longer exposure times than prior art camera devices. The present invention further affords an operator a wider range of options for the defining the temporal characteristics of individual exposures. Shutter means in the present invention are capable of exposing or blocking the exposure of the entire frame for much shorter intervals of time than are the shutters in the prior art. The present invention is also capable of more complicated exposure patterns than the prior art. Specifically, its shutters are distinguished by an ability to intervene during an ongoing exposure; each intervention consisting of a momentary, full frame blockage of the ongoing exposure.
Accordingly, a problem has existed heretofore in the fields of motion pictures and videoxe2x80x94namely that the ability of practitioners in those fields to manipulate the visual characteristics of the moving images that they create has been impeded by a set of limitations inherent in the prior art. From all the foregoing it can be appreciated that the prior art has not solved the problem of providing the practical means or methods necessary for overcoming those limitations, and for creating a variety of visual effects by creating and manipulating multiple optical images, and by manipulating the recording and subsequent combination of multiple related moving image sequences.